The piston interior delimits a hydraulic pressure chamber, i.e. determines the effective hydraulic piston surface, and at the same time defines a receiver and geometric interface for a rotation-translation converter (spindle-nut gear mechanism or preferably ball-screw drive (KGT)) of an actuator unit.
DE 10 2012 203 162, which is incorporated by reference describes a generic and robust brake piston construction with a dish-like pressure piece. For twist prevention, designed reinforced for ease of maintenance, between the piston and nut, accordingly it is provided that the piston has a collar at its open end, wherein its free edge is specially profiled so as to create reinforced twist-prevention means.